Biology subjects

Iwakiri, Y.

Publications and source records attributed to Iwakiri, Y..

3 recordsLinked to original sources

bioRxiv2020

Enhanced meningeal lymphatic drainage ameliorates neuroinflammation and hepatic encephalopathy in cirrhotic rats

Background and aimsHepatic encephalopathy (HE) is a serious neurological complication in patients with liver cirrhosis. Nothing is known about the role of the meningeal lymphatic system in HE. We tested our hypothesis that enhancement of meningeal lymphatic drainage could decrease neuroinflammation and ameliorate HE. MethodsA 4-week bile duct ligation (BDL) model was used to develop cirrhosis with HE in rats. Brain inflammation in patients with HE was evaluated using archived GSE41919. Motor function of rats was assessed by the rotarod test. AAV8-VEGF-C was injected into the cisterna magna of BDL rats one day after surgery to induce meningeal lymphangiogenesis. ResultsCirrhotic rats with HE showed significantly increased microglia activation in the middle region of the cortex (p<0.001) as well as increased neuroinflammation as indicated by significant increases in IL-1{beta}, INF{gamma}, TNF and Iba1 expression in at least one of the three regions of the cortex. Motor function was also impaired in rats with HE (p<0.05). Human brains of cirrhotic patients with HE also exhibited upregulation of pro-inflammatory genes (NF-{kappa}{beta}, Iba1, TNF and IL-1{beta}) (n=6). AAV8-VEGF-C injection significantly increased meningeal lymphangiogenesis (p=0.035) and tracer dye uptake in the anterior and middle regions of the cortex (p=0.006 & 0.003, respectively), their corresponding meninges (p=0.086 & 0.006, respectively) and the draining lymph nodes (p=0.02). Further, AAV8-VEGF-C decreased microglia activation (p<0.001) and neuroinflammation, and ameliorated motor dysfunction (p=0.024). ConclusionPromoting meningeal lymphatic drainage and enhancing waste clearance improves HE. Manipulation of meningeal lymphangiogenesis could be a new therapeutic strategy for the treatment of HE.

neuroscience↗

bioRxiv2020

Single-cell transcriptomics reveals zone-specific alterations of liver sinusoidal endothelial cells in cirrhosis

Dysfunction of liver endothelial cells (ECs), particularly sinusoidal endothelial cells (LSECs), is permissive for the progression of liver fibrosis/cirrhosis and responsible for its clinical complications. Here, we have mapped the spatial distribution of heterogeneous liver ECs in normal versus cirrhotic mouse livers and identified zone-specific transcriptomic changes of LSECs associated with liver cirrhosis using single-cell RNA sequencing technology. We identified 6 clusters of liver EC populations including 3 clusters of LSECs, 2 clusters of vascular ECs and 1 cluster of lymphatic ECs. To add finer detail, we mapped the 3 clusters of LSECs to Zones 1 to 3. We found that heterogeneous liver EC identities are conserved even in liver cirrhosis and that Zone 3 LSECs are most susceptible to damage associated with liver cirrhosis, demonstrating increased capillarization and decreased ability to regulate endocytosis. Altogether, this study deepens our knowledge of the pathogenesis of liver cirrhosis at a spatial, cell-specific level, which is indispensable for the development of novel therapeutic strategies to target the most highly dysfunctional liver ECs.

cell biology↗

bioRxiv2019

O-GlcNAc transferase suppresses necroptosis and liver fibrosis

Over a billion people suffer from chronic liver diseases worldwide, which often leads to fibrosis and then cirrhosis. Treatments for fibrosis remain experimental, in part because no unifying mechanism has been identified that initiates liver fibrosis. Here we report that O-linked {beta}-N-acetylglucosamine (O-GlcNAc) modification protects against hepatocyte necroptosis and initiation of liver fibrosis. Decreased O-GlcNAc levels were seen in patients with liver cirrhosis and in mice with ethanol-induced liver injury. Liver-specific O-GlcNAc transferase (OGT) knockout (OGT-LKO) mice exhibited ballooning degeneration and elevated circulating alanine aminotransferase (ALT) levels at an early age and progressed to liver fibrosis and portal inflammation by 10 weeks of age. OGT-deficient hepatocytes underwent excessive necroptosis and exhibited elevated protein expression levels of receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like (MLKL), which are key mediators of necroptosis. Furthermore, glycosylation of RIPK3 by OGT reduced RIPK3 protein stability. Taken together, these findings identify OGT as a key suppressor of hepatocyte necroptosis and OGT-LKO mice may serve as an effective spontaneous genetic model of liver fibrosis.

physiology↗